+- Scivillage.com Casual Discussion Science Forum (https://www.scivillage.com)
+-- Forum: Science (https://www.scivillage.com/forum-61.html)
+--- Forum: Biochemistry, Biology & Virology (https://www.scivillage.com/forum-76.html)
+--- Thread: Common traits of species facing extinction + Ant division of labor goes back 100mil y (/thread-11794.html)
Common traits of species facing extinction + Ant division of labor goes back 100mil y - C C - Feb 22, 2022
There are common traits among mammal and bird species facing extinction, scientists say
https://www.abc.net.au/news/science/2022-02-24/extinction-mammal-birds-common-traits-put-them-at-risk/100847984
KEY POINTS: Scientists have investigated the traits that make some animals more likely to be listed as endangered. Most at risk were bird species that grow fast and have lots of offspring; and mammal species with long turnover times between generations. In Australia, mammals with medium body sizes are most at risk due to feral cats and foxes.
INTRO: Whether directly through habitat destruction and overharvesting, or indirectly through introduced pests and climate change, we're driving what is often described as an extinction crisis. When invertebrates are factored in, some argue that we're in the early phase of the sixth mass extinction — the other five being Earth-altering periods such as the Cretaceous-tertiary (dinosaur) extinction, where more than 70 per cent of species died out.
But what if there are traits that make animals more susceptible to being wiped out? Could that help us identify those most at risk? To find out, scientists looked at 74 species of mammals and birds from around the world that also had sufficient data on their phylogenetics, life history traits and conservation status.
They found traits that many of those facing extinction have in common.
For mammals, the results are probably not too surprising. But for birds, there are some factors that don't seem to follow a simple path of logic. Their findings were published today in PLOS One... (MORE - details)
Division of labor in ants goes back over 100 million years
https://www.uni-jena.de/en/220222-ameisen-im-bernstein
RELEASE: Ants live in states organised according to the division of tasks. There are three castes, each of which has a different role: the queen lays eggs and the males fertilise them, while the workers look after the offspring and deal with finding food and nest-building. In biology, this special behaviour is called eusociality, which is developed in a particularly complex way in ants, as it is shown not only in their behaviour, but also in their morphology. Winged females take on the role of the queen, while wingless, infertile females perform the tasks of the workers.
But when exactly in their evolution did ants start this unique teamwork? The research team has now established that this cooperative way of life developed in the early Cretaceous period and the scientists present their findings in the research journal Zoological Journal of the Linnean Society.
In their work, the biologists closely examined four fossils enclosed in amber. These were three adult female wingless ants and one incompletely developed pupa – the first ant pupa ever found in Cretaceous amber.
“With the help of micro-computed tomography images, we were able to determine that the soft tissues of the insects have been exceptionally well-preserved,” explains Dr Brendon E. Boudinot, who is currently working at the University of Jena under a Humboldt Research Fellowship. “This enabled us to examine the precise structure of the brain and the transverse muscle fibres, for example, and thus compare the four specimens with each other in fine detail.”
Based on these insights into the ants’ internal anatomy, the researchers were able to draw conclusions about the species – and in doing so to make two spectacular discoveries. First, they established that two of the adult insects belong to a previously unknown species of the extinct ant genus Gerontoformica, which the biologists have now been able to describe more precisely for the first time.
Second, the third adult ant and the pupa are both of the same species: Gerontoformica gracilis. “As ant pupae are not mobile, it can be inferred that the adult insect carried it,” says US entomologist Boudinot. “This brood transport, as it’s called, is a unique feature of ant coexistence based on their division of labour.
The fossil therefore provides the first material evidence of cooperative behaviour from the Cretaceous period: these ants looked after their young together, went in search of food together and had different queen and worker castes.” The fossil representatives of the extinct ant genus are therefore an important “missing link” between today’s ants and their closest relatives, confirming that the specialised social system of ants evolved sometime in the early Cretaceous – during the time of the dinosaurs.
The work on the four fossil ants has shown the researchers the wealth of information that can be produced using the high-resolution imaging facilities. “We can now derive new insights into the development of the internal anatomy of fossil insects and clarify much more precisely the relationships of fossil species to each other and to species living today,” says Boudinot.
For example, how did the two different female forms of ants – queens and workers – develop? Did the wings regress first and then fertility, did the onset of sterility lead to the loss of the wings or did both developments take place at the same time? Thanks to the new findings and methods, scientists may soon be able to provide answers to such questions about the evolution of ants. There are also new, connected, research questions in the field of sociobiology, for example on the emergence of eusociality.